Railway traffic controlling apparatus



June 9, 1936. F. H. NICHOLSON ET AL 2,043,757

/ RAILWAY TRAFFIC CbNTROLLING APPARATUS Original Filed Nov. 24, v1933 1 INVENiORS Fran]: H.1Vl0h0ls0n and BY Harold WfBPgq/z.

THEIR ATTORNEY Patented June 9, 1936 l UNITED STATES RAILWAY 2,043,767 PATENT OFFICE TRAFFIC CONTROLLING APPARATUS Frank H. Nicholson, Edgewood, and Harold W.

Bryan,

Wilkinsburg, Pa.,

si no s to Th Union Switch & Signal. Company, swissvale, ;Pa., a corporation of Pennsylvania .Aiinli ation No emb r 24, 1.933. Se al N 69 .540

Renewed November 193d 10 Claims. I (01. 24634) The accompanying drawing is a diagrammatic view showing one form of apparatus embodying our invention as applied to a stretch of railway track equipped for wayside and cab signaling.

Referring to the drawing, the reference characters l--2 and 23 designate two adjoining sections of a stretch of track over which trafiic normally moves from left to. rightin the dinection 0f the arrow. ,Each track section is electrically insulated from adjoining sections by insulated rail joints, in the usual manner. Section .l,Z,. 's normally supplied with coded rail current. from a transformer T and section 2Y-3 is similarly supplied with rail current from a transformer T For purposes of illustration, thefrail current will be assumed to be of theusual frequency code, comprising alternating current periodicallyyaried at a frequency of 180,120 .or .80 impulses per minute, in accordance with traificconditions in advance. The rail current is coded by ,a suit- .able .code transmitter CT for each section, having the periodically operated contacts J81), 131], and 80, which furnish the ,l80, 12D and 80 code frequencies, respectively. j V Considering section 2-+.3, the direct current code-following track relay TR energized through the relay transformer RT and rectifier R3, periodically reverses the flow of direct current from a source B--C, in the primary winding of the decoding transformer D'I thereby inducingan alternating secondary voltage :of a frequency corresponding to the .code being followed ,by the track relay. The decoding relay H energized through rectifier EH is non-selective as to code and responds to operation of the track relay ,on'any one of the 18.0, 12.0 or 80 codefreouencies. pecoding relay E ,,however, is selectiye and will relspond only to 120 code because of electricaltuning by means of the usual tunin unit DE comprising a reactor, condenserandrectifier. Sim larly, the decoding relay F ,will. respond on y to 180 code because of the interposition ofa similar a unit .DF tuned to the 18.0 code. ,Since thetuning units DE and JDF are well lrnoyvn, the elements comprising these units name not ,beemshownin .detail. c j

,The protection relay LP controls 2the,application .of the 120,.and:130Lc0delirfiq11encies to the rear section .l--2 and is fillfl eientlyflslow releasies oran he.9a ei 9e.=i a kn y on anyone of the three codes. That is, as long as relay is following code, relay LP will be maintained energized over front contacts 4 and .5 of relays TR H respectively. The indications of signals? are selectively controlled by the group of relays H LPF, E and F in a manner which will be obvious from the drawing, and it is deemed unnecessary to trace the signal control circuits in detail.

-We shall next explain the operation of the system as a whole. If at least two sections in-ad Vance of section 2-. 3 are unoccupied, 180 code will s pplied to section 2-4 from transformer T Under this condition, if section 2-3 is also unoccupied, relay TR will be following 180 code,

and relays H LP and F will all be energized. Consequently, 180 ,code'will be supplied to the rear section l 2 over a circuit which includes the following: one terminal BX of a source of current, front contact .6 of relay T3 front point of contact 1 of relayF front contact .8 of relay LP front point of contact-9 .of relay H and the winding of track transformer ,110 the other terminal CX of the source. It should be noted that the above circuit does not include the 180 code contact of code transmitter GT the 180 code for section l2 being produced through the periodic operation of eontact 6 when relay IE is following 1,80 code.

, If but one section in advance .of section 2-3 is unoccupied, relay TR will be following 120 code, and relays, H LP and '15 will be energized. IITherearsection will again receive 18 code, but the circuit will now include: contact 1,8,0 of code transmitter 011?, front point of ,con-

tact l9 of relay E back point of contact 1 of relay, F3, front contact 8 of relay LP, and

front Po nt of contact 9 ,Qf relay H .If ,the

section in ad am o of section 273 is occupied,

relay TR will be following .80 code, and re-.

lays H and LP. .will Joe energized. Section ,l 2 ,will, therefore, receive 120 code over a circuit which includes the-following: contact 120, of transm tter, b ck c nof Contact Lll of relay .E back ,DQillt ,ofcontact I of relay ,F and the ;f,ront,-eoritaot B and flbnt point of contact 9 of relays ,LP and H as before. If section 2: 3 occupied, section l-.-2 will receive 80 codepver a circuit which includes the ,80 code contact of transmitter QTZ, and

'lease operations and the flashing any reason, such for example as a train entering section 2-3 from a siding, or the reversal of a switch in the section, the shunt-, ing of relay TR will cause an interruption in the supply of 180 code to the rear section l2.

If the rail joints between sections 23 and l2 break down at a time when these sections are supplied with fcode and code, respectively, relay TR will have both 80 and 120 code in its windings and will operate erratically. If the energization of relay E is excessive, this relay may pick up intermittently under this condition, resulting in a flashing indication of signal S Ordinarily, unless relay H is considerably over-energized, the erratic code resulting from the inter-action of the 80 and 120 codes will cause relay H to release, whereupon 80 code will be supplied tothe rear section over the back point of contact 9 of relay H It has been found in practice that if the rail joints break down when sections 2-3 and l2 are supplied with 120 and code, respectively, the erratic code resulting will fail to pick up relay F Usually relay E will also be released, thus preventing a false signal indication. 7

Let it next be assumed that while a train is cocupying section 2 -3, the rail joints between sections 2-3 and l2 break down, permitting 80 code current from the rear section to operate relay TR? Relay TR?, in following 80 code, will cause relay H to become energized, thus interrupting the 80 code at the back point of contact 9, whereupon relays TR and H will both become deenergized. This operation will repeat itself periodically, and will cause signal S to display a flashing indication which provides a distinctive warning of the rail joint insulation failure. It is understood that the pickup time ofrelay LP is made sufficiently long to prevent pick up of this relay under the above condition.

Under ordinary conditions, no code other than 80 can influence the track relay of an occupied section, with the rail joints broken down, because stepping up of the code to 120 or 180 is prevented at the 80 code stage. 'A different result may follow, however, if it be assumed that while sections l2 and 2-3 are being supplied with 180 code,'the rail joints at location 2 break down and a train enters section 2-3 from a siding, particularly if it be assumed that sufficient 180 code energy passes over the rail joints from transformer T to operate relay TR?.

Since, under the above condition, the energy for transformer T and therefore for relay TR? is carried over the front contact 6, a momentary stick circuit over the front contacts 6, 1, 8 and 9 of relays TR?, F LP and H will become effective to supply steady energy to transformer T and so to hold relay TR? picked up on steady energyywhereupon relays F H and LP will release. Therefore, the stick circuit will be broken and the release of relay H will cause 80 code to be applied tosection l2, resulting in the sequence of alternate 80 code pickup and resignal indication described above. I

Let it next be assumed that the rail joints are broken down and a train enters section 2--3 from a siding at a time such that section 2--3 is receiving 120 code and section l2 is receiving 180 code. Under this condition, relays E LP, and H will be energized so that transformer T will be receiving 180 code over contact I80 of code transmitter CT front contacts In, 8, and 9 of the foregoing relays, and back contact 1 of relay F However, should relay TR? begin to operate on 180 code passing over the joints 5 from transformer T relay F will pick up, transferring the supply of energy from contact I80 of transmitter CT to front contact 6 of relay TR?, assuming for the moment that front contact I became closed during the time that front contact 6 was also closed. Relay TR? will now be held up over the stick circuit previously described until relay H releases and causes 80 code to be supplied to transformer T and causes a flashing indication to be displayed by signal S Relay F is sufficiently slow releasing to permit relay H to release under this condition, in order to prevent 120 code from being applied to transformer T and to insure that the flashing indication resulting from 80 code operation of relay TR? will be obtained.

If front contact 1 of relay F closes at a time when contact 6 of relay TR? is open, the abovementioned stick circuit will not be completed and relay TR? will remain deenergized for an interval, bringing about the release of relays F H and LP As soon as relay H releases, 80 code will be applied to section l2, and the flashing signal indication will again be produced.

If the rail joints break down and a train enters section 2--3 from a siding at a time when this section is receiving 80 code and the rear section l2 is receiving 120 code, then, should relay TR? follow the 120 code from the rear'section, relay E will pick up and will step up the code for the rear section to 180. The operation from this point on will be the same as previously described, that is, relay TR? will either be maintained energized or deenergized for a prolonged interval, ac-

cording as front contact I of relay F becomes l closed at a time when contact 6 of relay TR? is closed or is open, respectively. In either case, the erratic 80 code will again be furnished to section l2 and signal S will display a flashing indication.

From the foregoing description, it will be apparent that irrespective of the particular codes being eifective in the adjoining track sections at the time when the rail joints break down and a dangerous traffic move occurs, the apparatus 5 disclosed will provide protection by preventing a clear signal from being displayed, and by providing a distinctive indication as a Warning of this particular type of failure. Although the frequency code has been used for purposes of illustration, it will be understood that the code may be of any suitable type, and may be either alternating or direct current.

Although we have herein shown and described only one form of railway traflic controlling apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention. 6

Having thus described our invention, what we claim is:

1. In combination, two adjoining sections of railway track, a source of coded current and a code-following track relay connected with the tact of said track relay and a contact of said slow acting relay for supplying rail current to the other of said two sections.

2. In combination, two adjoining sections of railway track, means for supplying coded rail current to one of said sections, a code-following track relay for said one section, a decoding relay which becomes energized in response to code operation of said track relay, a slow acting relay energized over a front contact of said track relay and a front contact of said decoding relay, and means including a front contact of said track relay and a front contact of said slow acting relay for supplying rail current to the other of said two sections.

3. In combination, two adjoining sections of railway track, means for supplying one of said sections with rail current of a first or of a second code in accordance with trafiic conditions, a code-following track relay for said one section, a first and a second decoding relay responsive to code operation of said track relay on said first and said second code respectively, means including a back contact of said first decoding relay for at times supplying rail current to the other of said two sections, and means including a front contact of said track relay and a front contact of said second decoding relay for at other times supplying rail current to said other section.

4. In combination, two adjoining sections of railway track, means for supplying one of said sections with rail current of a first or of a second code in accordance with traflic conditions, a codefollowing track relay for said one section, a first decoding relay which becomes energized in re sponse to operation of said track relay on either said first or said second code, a second decoding relay which becomes energized in response to operation of said track relay on said second code, means including a back contact of said first decoding relay for supplying rail current of said first code to the other of said two sections, and means including a front contact of said track relay and a front contact of said second decoding relay for supplying rail current of said second code to said other section.

5. In combination, two adjoining sections of railway track, means for supplying one of said sections with rail current of a first or of a second code in accordance with traific conditions, a code following track relay for said one section, a first decoding relay which becomes energized in response to operation of said track relay on either said first or said second code, a second decoding relay which becomes energized in response to operation of said track relay on said second code, a slow acting relay controlled over a contact of said track relay and a front contact of said first decoding relay and capable of bridging the code operation of said track relay, means including a back contact of said first decoding relay for supplying rail current of said first code to the other of said two sections, and means controlled by said slow acting relay as well as said second decoding relay and including a front contact of said track relay for supplying rail current of said second code to said other section.

6. In combination, two adjoining sections of railway track, means for supplying one of said sections with rail current of a first or of a second code in accordance with trafiic conditions, a code following track relay for said one section, a first decoding relay which becomes energized in response to operation of said track relay on either said first or said second code, a second decoding relay which becomes energized in response tooperation of said track relay on said second code, a slow acting relay energized over a front contact of said track relay and a front contact of said first decoding relay and capable of bridging the code operation of said track relay, means including a back contact of said first decoding relay for supplying rail current of said first code to the other of said two sections; and means including a front contact of said first decoding relay, a front contact of said slow acting relay, a front contact of said second decoding relay, and a front contact of said track relay for supplying rail current of said second code to said other section.

7. In combination, two adjoining sections of railway track, means for supplying current of a first or of a second code to one of said sections in accordance with traffic conditions, a code following track relay for said one section, a coding device, means controlled by said track relay and effective when said one section is supplied with current of said first code for repeating the first code into said second section, and means effective when said one section is supplied with current of said second code for rendering said coding device effective to supply current of 'said first code to said other section.

8. In combination, two adjoining sections of railway track, means for supplying current of a first or of a second code to one of said sections in accordance with trafilc conditions, a code following track relay for said one section, a coding device, means eifective when said one section is supplied with current of said first code for repeating the first code into said second section over a contact of said, track relay, and means effective when said one section is supplied with current of said second code for rendering said coding device efiective to supply current of said first code to said other section.

9. In combination, two adjoining sections of railway track, means for supplying current of a first or of a second code to one of said sections, a code following relay controlled by current supplied to said one section, means controlled by said relay and efiective when said one section is supplied with current of said first code for repeating the first code into said second section, and means exclusive of said relay and effective when said one section is supplied with current of said second code for supplying current of said first code to said other section.

10. In combination,- two adjoining sections of railway track, means for supplying current of a first or of .a second code to one of said sections, a code following relay controlled by current supplied to said one section, means effective when said one section is supplied with current of said first code for repeating the first code into said second section over-a contact of said relay, and means exclusive of said contact and. effective when said one section is supplied with current of said second code for supplying current of said first code to said other section.

FRANK H. NICHOLSON. HAROLD W. BRYAN. 

